Inspection tool

ABSTRACT

A tool is receivable into an interior region of a core shroud of a Boiling Water Reactor. The tool includes an elongated frame, an elevator apparatus situated on the frame, and a manipulator apparatus situated on the elevator apparatus. The tool further includes a reciprocation apparatus that is situated on the manipulator apparatus and that has a mount that is structured to carry a device thereon. The reciprocation apparatus includes an elongated rack of an arcuate profile. The elevator apparatus is operable to move the reciprocation apparatus along the longitudinal extent of the frame. The tool further includes a foot apparatus that is situated at an end of the frame and that is receivable on a core plate to enable the frame to be pivoted about an axis of elongation of the frame with respect to the core plate.

BACKGROUND 1. Field

The disclosed and claimed concept relates generally to a tool that isusable in an irradiated environment and, more particularly, to a toolthat is usable to be received into an interior region of a core shroudof a boiling water reactor and that is structured to carry a devicethereon into the interior region.

2. Related Art

Numerous types of nuclear reactors are known to exist in the relevantart. Such known nuclear reactors can be said to include pressurizedwater reactors (PWRs) and boiling water reactors (BWRs), each of whichtypically is connected with an electrical generator as part of a nuclearpower plant.

Various components and structures in a nuclear reactor are examinedperiodically to assess the structural integrity of such components andstructures and to indicate the need for repair. Ultrasonic inspection isa known technique for detecting cracks in nuclear reactor components andstructures. However, the inspection areas in a nuclear reactor may havelimited access and therefore may be difficult to assess using aninspection tool. For example, the reactor core shrouds of BWRs areperiodically assessed for cracking inasmuch as the presence of crackingcan diminish the structural integrity of the core shroud and can disruptplant operations. However, the core shroud welds are difficult toaccess. More specifically, access to such a core shroud at the outercylindrical surface is typically limited to the annular space betweenthe outer surface of the core shroud and the inner surface of a reactorpressure vessel in areas between adjacent jet pumps. Access for purposesof ultrasonic scanning is further restricted within the narrow spacebetween the inner surface of the reactor pressure vessel and the jetpumps and other attachments such as the riser brace or restrainerbrackets that protrude radially outwardly from the cylindrical outersurface of the core shroud. Furthermore, and depending upon the specificplant installation, some core shrouds and welded attachments may beentirely inaccessible at the exterior surface of the core shroud.

It is further noted that the inspection areas in a nuclear reactor canbe highly radioactive and can pose safety risks for personnel working inthese areas. The inspection and repairing of nuclear reactors, such asBWRs, typically consists of operating manually-controlled poles andropes to manipulate and/or position the inspection devices. During areactor shutdown, the servicing of some components requires theinstallation of inspection manipulation devices 30 to 100 feet deepwithin the reactor coolant. Relatively long durations are required toinstall or remove manipulators at such depths, which can impact theduration of the plant shutdown. In addition, different inspectiondevices can require several different manipulators or reconfigurationsof manipulators in order to perform an inspection, which requiresadditional manipulator installations and removals, and thus added cost.The long durations impact not only plant shutdown durations but alsohave the effect of increasing the radiation and contamination exposureto personnel performing the inspection operations.

Plant utilities thus have a desire to reduce the number of manipulatorinstallations and removals in order to reduce the radiological exposureas well as the cost and impact of plant outages. Furthermore, plantutilities have a desire to reduce cost and to operate as productively aspossible. Improvements thus would be desirable.

SUMMARY

An improved tool is configured to be received into an interior region ofa core shroud of a BWR. The tool is structured to carry thereon a deviceinto the interior region. The device can be a test instrument that iscapable of performing an ultrasonic scanning operation on the coreshroud, or it can be another device. The tool includes an elongatedframe, an elevator apparatus situated on the frame, and a manipulatorapparatus situated on the elevator apparatus. The tool further includesa reciprocation apparatus that is situated on the manipulator apparatusand that has a mount that is structured to carry the device thereon. Thereciprocation apparatus includes an elongated rack of an arcuate profilethat matches the profile of the inner surface of the core shroud.Movement of the elongated rack with respect to the manipulator apparatuscauses a mount that is situated on the rack and the device that iscarried on the mount to move along an arcuate path to inspect the coreshroud along a circumferential direction. The elevator apparatus isoperable to move the reciprocation apparatus along the longitudinalextent of the frame in order to move the mount and the device carriedthereon along an axial direction on the core shroud. The manipulatorapparatus is operable to move the reciprocation apparatus between aretracted position received in an elongated receptacle formed on theframe and a deployed position wherein the reciprocation apparatus isremoved from the receptacle and the device is therefore deployed forinspection purposes. In the retracted position, the tool is receivablethrough an opening in a top guide of the BWR and into a fuel cell fromwhich the nuclear fuel has been removed. The tool further includes afoot apparatus that is situated at an end of the frame and that isreceivable on a core plate to enable the frame to be pivoted about anaxis of elongation of the frame with respect to the core plate.

Accordingly, an aspect of the disclosed and claimed concept is toprovide an improved tool that is structured to be received in aninterior region of a core shroud of a BWR and that is structured tocarry an inspection device or other device thereon into the interiorregion.

Another aspect of the disclosed and claimed concept is to provide animproved tool that can be received through an opening in the top guideand into a fuel cell of the BWR from which the nuclear fuel has beenremoved.

Another aspect of the disclosed and claimed concept is to provide animproved tool having a reciprocation apparatus that is operable to movea device that is situated on a mount along an arcuate path along aninterior surface of the core shroud of the BWR.

Another aspect of the disclosed and claimed concept is to provide areciprocation apparatus that is receivable on such a tool and that isadapted to enable movement of a device that is situated on a mount of areciprocation apparatus along an arcuate path.

Another aspect of the disclosed and claimed concept is to provide animproved tool having a manipulator apparatus that is mountable on anelevator apparatus in either of a pair of configurations, in oneconfiguration the manipulator apparatus extending from the elevatorapparatus in a direction generally toward the foot apparatus, and in asecond configuration the manipulator apparatus extending from theelevator apparatus in a direction generally away from the footapparatus.

These and other aspects of the disclosed and claimed concept areprovided by an improved tool that is structured to be received into aninterior region of a core shroud of a boiling water reactor and that isstructured to carry a device thereon into the interior region. The toolcan be generally described as including a frame, the frame beingelongated along an axis of elongation and having a receptacle formedtherein that is elongated along the axis of elongation, an elevatorapparatus situated on the frame, a manipulator apparatus situated on theelevator apparatus, at least a portion of the manipulator apparatusbeing situated in the receptacle, a reciprocation apparatus that can begenerally described as including a support that is elongated and that issituated on the manipulator apparatus, the reciprocation apparatusfurther can be generally described as including a mount that is situatedon the support and that is structured to carry the device, the elevatorapparatus being operable to move the manipulator apparatus between afirst position and a second position along the longitudinal extent ofthe frame, the manipulator apparatus being operable to move thereciprocation apparatus between a first position wherein the support isdisposed at least in part in the receptacle and a second positionwherein the support and the mount are removed from the receptacle, and afoot apparatus situated on the frame and that can be generally describedas including a number of feet and a pivot mechanism, the number of feetbeing situated at an end of the frame and being structured to bereceived on at least one of a fuel support, a control rod guide tube,and a core plate of the boiling water reactor, the pivot mechanism beingstructured to pivot the frame about the axis of elongation with respectto the number of feet when the number of feet are received on the atleast one of the fuel support, the control rod guide tube, and the coreplate.

Other aspects of the disclosed and claimed concept are provided by animproved reciprocation apparatus that is structured to be mounted to atool which is receivable into an interior region of a core shroud of aboiling water reactor, the reciprocation apparatus further beingstructured to carry a device thereon into the interior region. Thereciprocation apparatus can be generally stated as including a platformthat is structured to be situated on the tool and that has a first sideand a second side opposite one another, a support that is elongated andthat is situated on the platform, the support having a first end and asecond end opposite one another, the support being movable along itsdirection of elongation with respect to the platform in a firstdirection wherein the first end moves relatively farther away from thefirst side, the support further being movable in a second directionopposite the first direction wherein the second end moves relativelyfarther away from the second side, a belt that is elongated andflexible, the belt being affixed at one or more locations along itslength to the platform to form a closed loop that extends about at leasta portion of the support and that permits relative movement between thebelt and the at least portion of the support when the support moves inthe first and second directions, a mount that is situated on the beltand that is structured to carry the device, a drive mechanismoperationally extending between the support and one of the platform andthe belt, the drive mechanism being operable to move the reciprocationapparatus between a first state of the reciprocation apparatus and asecond state of the reciprocation apparatus, in the first state, arelatively greater portion of the support extends from the first sidethan extends from the second side, and the mount is situated relativelycloser to the first end than the second end, and in the second state, arelatively greater portion of the support extends from the second sidethan extends from the first side, and the mount is situated relativelycloser to the second end than the first end.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the disclosed and claimed concept can begained from the following Description when read in conjunction with theaccompanying drawings in which:

FIG. 1 is a perspective view of an improved tool in accordance with afirst aspect of the disclosed and claimed concept having situatedthereon a manipulator apparatus that is situated in a firstconfiguration on the tool, and further showing an improved reciprocationapparatus in accordance with another aspect of the disclosed and claimedconcept situated on the manipulator apparatus in a centered position;

FIG. 2 is a top plan view of the tool of FIG. 1 as seen through a topguide of a boiling water reactor and situated in a fuel cell anddisposed on a core plate of the boiling water reactor;

FIG. 3 is a view similar to FIG. 1, except depicting the manipulatorapparatus positioned at a different location along the longitudinalextent of the tool;

FIG. 4 is an elevational view of the tool of FIG. 1 received in theboiling water reactor of FIG. 2 and with the manipulator apparatus beingdepicted in a second configuration on the tool;

FIG. 5 is a view similar to FIG. 1, except depicting the manipulatorapparatus in the second configuration and further depicting thereciprocation apparatus in a different, non-centered position;

FIG. 6 is a view similar to FIG. 5, except depicting the manipulatorapparatus at a different position along the longitudinal extent of thetool and depicting the reciprocation apparatus situated at a locationbeyond a frame of the tool and situated adjacent a foot apparatus of thetool;

FIG. 7 is a view similar to FIG. 6, except depicting a top plan view ofthe tool;

FIG. 8 is a view similar to FIG. 6, except depicting a front view of thetool;

FIG. 9 is a view similar to FIG. 5, except depicting the manipulatorapparatus in a retracted position wherein a support of the reciprocationapparatus is situated within an elongated receptacle of the frame;

FIG. 10 is a view similar to FIG. 9, except depicting a side view of thetool;

FIG. 11 is a sectional view as taken along line 11-11 of FIG. 9;

FIG. 11A is an enlargement of an indicated portion of FIG. 11;

FIG. 12 is a view similar to FIG. 9, except depicting a top plan view ofthe tool;

FIG. 13 is a side elevational view of the manipulator apparatus of thetool of FIG. 1;

FIG. 14 is a front elevational view of the manipulator apparatus of FIG.13;

FIG. 15 is a sectional view as taken along line 15-15 of FIG. 13;

FIG. 16 is a perspective view of the manipulator apparatus and thereciprocation apparatus in a position similar to that depicted in FIG.5;

FIG. 17 is a view similar to FIG. 16, except depicting the reciprocationapparatus in a different position with respect to the manipulatorapparatus;

FIG. 18 is a view similar to FIG. 16, except depicting a front view ofthe manipulator apparatus and the reciprocation apparatus;

FIG. 19 is a top plan view of the reciprocation apparatus of FIG. 1;

FIG. 20 is a rear elevational view of the reciprocation apparatus ofFIG. 19;

FIG. 21 is a view similar to FIG. 19, except depicting the reciprocationapparatus in another position; and

FIG. 22 is a sectional view as taken along line 22-22 of FIG. 19.

Similar numerals refer to similar parts throughout the specification.

DESCRIPTION

An improved tool 4 in accordance with an aspect of the disclosed andclaimed concept is depicted generally in FIGS. 1-12 and is depicted inpart in FIGS. 13-22. The tool 4 is configured to carry a device 6 (FIG.7) thereon into an interior region 8 of a nuclear reactor such as aboiling water reactor (BWR) 10, as is depicted in FIG. 2. The device 6may be, for example, an ultrasonic testing device or other such testingor evaluation device, or it alternatively might be some type of a devicethat physically interacts with an object at the interior region 8, suchas a device that grasps or moves an object within the interior region 8,by way of example and without limitation.

As can be seen in FIG. 2, the BWR 10 includes an annular shroud 12 thatis situated within the interior region of a reactor pressure vessel 15.The shroud 12 has an interior surface 14 that faces away from thereactor pressure vessel 13 and that is the surface of the shroud 12 atwhich an inspection of the shroud 12 can be conducted with the use ofthe tool 4, such as if the device 6 is an ultrasonic sensor. As can beunderstood from FIG. 4, the shroud 12 has a number of welds formedtherein that include a vertical weld 16 and a horizontal weld 18. Asemployed herein, the expression “a number of” and variations thereofshall refer broadly to any non-zero quantity, including a quantity ofone. The vertical weld 16 can be said to extend along an axial direction17 of the shroud 12, and the horizontal weld 18 can be said to lie alonga circumferential direction 19 which can also be referred to herein asan azimuthal direction.

As can be understood from FIG. 2, the BWR 10 further includes a coreplate 20 upon which the tool 4 can be situated and a top guide 26 thatis spaced vertically above the core plate 20. The BWR 10 has a pluralityof fuel cells 22 formed therein that each include an opening formed inthe top guide 26, and each of which is structured to have nuclear fuelsituated therein when the BWR 10 is in operation. Furthermore, it isnoted that the BWR 10 is depicted herein, i.e., in FIGS. 2 and 4, ashaving all of the fuel removed therefrom for purposes of simplicity ofdepiction. It is also expressly noted that the tool 4 is designed to beused in conjunction with the BWR 10 without the need to remove all ofthe fuel and other materials from the fuel cells 22. That is, the tool 4is advantageously configured to be received in a fuel cell 22 after thefuel has been removed therefrom, but with a minimal need to remove fuelfrom the fuel cells 22 adjacent thereto. For example, FIG. 2 depicts thetool 4 being received in a fuel cell 22A of the plurality of fuel cells22. FIG. 2 also depicts the tool 4 being pivoted (in a fashion that willbe described in greater detail below) such that a portion thereofprotrudes into an adjacent fuel cell 22B and into an adjacent region 22Cthat does not actually receive fuel therein. As such, it can beunderstood that the other fuel cells 22 that are depicted in FIG. 2 asbeing without fuel and the like need not have their fuel and the likeremoved therefrom in order to receive the tool 4 in the fuel cell 22Aand have it perform an inspection on the interior surface 14 in thevicinity of the fuel cells 22A and 22B, and in such circumstances it isnecessary only to remove the fuel from the fuel cells 22A and 22B. Thisadvantageously reduces the time and effort required to perform aninspection on the interior surface 14 of the shroud 12 by limiting theamount of fuel that must be removed from the fuel cells 22 in order toperform the inspection operation on the interior surface 14 of theshroud 12.

As can further be seen in FIG. 2, the core plate 20 has a plurality ofsockets formed therein that are indicated generally at the numerals 24A,24B, 24C, and 24D, and which can be collectively or individuallyreferred to herein with the numeral 24. Each fuel cell 22 has a set ofsockets 24A, 24B, 24C, and 24D that are configured to receive therein acooperating structure of the tool 4 that will be described in greaterdetail below. When the BWR 10 is in operation, the receptacles 24 acceptthe reactor fuel support casting and various fuel lattice structures. Itthus can be understood that when the BWR 10 is to be inspected or tohave an operation performed thereon with the tool 4, one of the fuelcells 22 that is situated nearby the interior surface 8 will need itsfuel removed therefrom in order to receive the tool 4 therein. The fuelthat is in one or two additional fuel cells 22 that are adjacent thefuel cell 22 that is to receive the tool 4 may need to be removed inorder to permit maneuvering of the tool 4 as will be described below.

As can be understood from FIG. 1, the tool 4 is connected with acomputer system 28 via an umbilical 30. The computer system 28 includesan input apparatus that can include various input devices such as akeyboard, joystick, and other control input devices. The computer system28 further includes an output apparatus that can include various outputdevices such as a visual display, a printer, an audible output systemsuch as a loudspeaker, and the like without limitation. The computersystem 28 additionally includes a processor apparatus that is incommunication with the input apparatus and the output apparatus andwhich has various routines executable thereon to cause the tool 4 toperform various operations. It is to be understood that the tool 4 andits various subassemblies are robotic in nature, meaning that theyinclude actuators that are operated electronically via electric motorsor via pneumatically-operated motors or cylinders, or the like. As such,it is understood that the umbilical 30 can include not only electroniccommunication channels in the form of wires and the like, but can alsoinclude air or other fluid channels that convey fluid to the tool 4 inorder to actuate certain subassemblies thereof. In this regard, it isunderstood that the computer system 28 may communicate wirelessly withthe tool 4 without departing from the spirit of the instant disclosure.

The tool 4 can be said to include an elongated frame 32 that iselongated along an axis of elongation 34. The tool 4 further includes afoot apparatus 36 that is situated at an end of the frame 32 and whichincludes a foot assembly 37 having set of four feet 38 that areconfigured to be received in the sockets 28A, 28B, 28C, and 28D of afuel cell 22 in which the tool 4 is received. In this regard, it isunderstood that the feet 38 can be received on any of a variety of partsof the BWR 10, such as any one or more of a fuel support, a control rodguide tube, or the core plate 20 of the BWR 10, by way of example. Thefuel support is a piece of reactor hardware that sits on the top of acontrol rod guide tube. The top of the control rod guide tube protrudesslightly through the top of the core plate 20 and supports the weight ofthe fuel support. The feet 38 can be reconfigured as needed to permitinstallation of the tool 4 into a guide tube or on the core plate 20, byway of example, if the customer has the control rod guide tube and/orthe fuel support removed.

The foot apparatus 36 further includes a pivot mechanism 40 that causesthe frame 32 to pivot with respect to the feet 38 about an axis ofrotation which, in the depicted exemplary embodiment, is coincident withthe axis of elongation 34. In this regard, the pivot mechanism 40includes a motor 42 that is connected via gears between the frame 32 andthe feet 38, and which can be energized or otherwise actuated to operatethe pivot mechanism 40 to pivot the frame 32 about its axis ofelongation 34 with respect to the feet 38. More specifically, and as isshown in FIG. 11A, the motor 42 includes a shaft 39 and further includesa pinion gear 41 situated on the shaft 39. The foot assembly 37 furtherincludes situated thereon a reaction gear 43 that is engaged by thepinion gear 41 to pivot the frame 32 about its axis of elongation 34with respect to the feet 38 when the motor 42 is energized or isotherwise actuated. A bearing 45 is interposed between the end of theframe 32 and the foot assembly 37 in order to reduce frictiontherebetween when the frame 32 is being pivoted with respect to the feet38. In the depicted exemplary embodiment, the bearing 45 is a deepgroove ball bearing, but it is understood that other types of bearingscan be employed without departing from the spirit of the instantdisclosure.

As can be seen in FIG. 1, for example, the frame 32 has an elongatedreceptacle 44 formed into what can be characterized as a frontal face 46of the frame 32. The receptacle 44 is elongated along the axis ofelongation 34. The frame 32 can be said to additionally include a rearface 48 (FIG. 2) opposite the frontal face 46, and to further include apair of chamfers 50A and 50B that are formed in the frame 32 and thatextend between the rear face 48 and the pair of lateral surfaces 51A and51B, respectively. As can be understood from FIG. 2, the chamfers 50Aand 50B, which may be collectively or individually referred to hereinwith the numeral 50, provide clearance between the frame 32 and the fuelcell 22 that is situated adjacent the fuel cell 22 where the tool 4 issituated. Such clearance enables the pivot mechanism 40 to pivot theframe 32 with respect to the core plate 20 without a meaningful risk ofstriking or otherwise engaging the fuel that is situated in suchadjacent fuel cell 22. It is noted that the chamfers 50 can be ofdifferent configurations and profiles, such as rounded radii orotherwise arcuate, or can be of other angles with respect to the rearface 48 and the lateral surfaces 51A and 51B without departing from thespirit of the instant disclosure.

As can be understood from FIGS. 1 and 2, by way of example, the frame 32includes a head 47 at an end thereof opposite the foot apparatus 36. Thehead 47 is of a round shape within a plane oriented transverse to theaxis of elongation 34. The head 47 has formed therein an access port 49that can receive therein another device such as a camera 53. The camera53 would typically be connected via a cable 55 with a video system, andthe cable 55 may be a part of the umbilical 30. By providing the pivotmechanism 40 at the bottom end of the tool 4 rather than at the top endof the tool 4 the head 47, the head 47 has sufficient free space insidethat it can advantageously have the access port 49 formed therein, whichpermits the camera 53 or other device to be received into the accessport 49. The access port 49 provides access into the receptacle 44,which enables access between the receptacle 44 and, for instance, theregion that is situated vertically above the tool 4. For instance, thecamera 53 can be received through the access port 49 into the receptacle44 in order to remotely observe the operations of the device 6 and thefunctioning of the tool 4.

Further advantageously, by providing the pivot mechanism 40 to besituated between the foot assembly 37 and the frame 44 and to thus pivotthe entire frame 44 with respect to the feet 38, the pivoting of theframe 44 about axis of elongation 34 can cause the umbilical 30 to movewithin the water that is situated in the BWR 10. That is, in certainsituations such as the removal of fuel from a fuel cell 22, the narrowconfines of the BWR may result in a physical conflict between theumbilical 30 and the fuel that is being removed, by way of example. Thepivot mechanism 40 thus can be advantageously operated to pivot theframe 44 and thus to thereby reposition the umbilical 30 within thewater of the BWR 10, thus resolving the conflict between the umbilical30 and the fuel being removed and therefore advantageously avoidingphysical contact between them.

The tool 4 further includes an elevator apparatus 52 that is depicted inFIG. 11 as being situated on the frame 32 and including a drive motor 54and a drive screw 56. The drive screw 56 is cooperable with a follower58 (FIG. 16). The drive motor 54 is operatively connected with the drivescrew 56, which is in the form of a jack screw or other type of threadedelongated device, and which is threadably connected with the follower58. As can be seen in FIG. 16, the follower 58 is affixed to amanipulator apparatus 60. As can be understood from FIGS. 8, 10, and 11,when the drive motor 54 is energized, or is otherwise caused to operate,the drive screw 56 is caused to rotate within the receptacle 44 and tothreadably engage the follower 58, which causes the follower 58 and themanipulator apparatus 60 to be translated along the axis of elongation34 of the frame 32. For example, the position of the manipulatorapparatus 60 in FIG. 1 with respect to the frame 32 is different thanthe position of the manipulator apparatus 60 in FIG. 3 with respect tothe frame 32. Such a translation of the manipulator apparatus 60 alongthe axis of elongation 34 results from the drive motor 54 of theelevator apparatus 52 having been energized or otherwise caused tooperate the drive screw 56 in order to threadably engage the follower 58and to translate the manipulator apparatus 60 within the receptacle 44along the axis of elongation 34.

As can be understood from FIGS. 1 and 16, by way of example, themanipulator apparatus 60 can be said to include an extension apparatus62 and a rotation apparatus 64 that are connected with one another. Theextension apparatus 62 is situated on the elevator apparatus 52, and therotation apparatus 64 is situated on the extension apparatus 62.

The extension apparatus 62 can be said to include a four bar linkage 66and a driver 68. As can best be seen in FIG. 16, the four bar linkage 66can be said to include a stand 69 upon which the follower 58 issituated, a first link 70 and a second link 72 that are pivotablyconnected with the stand 69 and that each extend away therefrom, and abody 74 that is pivotably connected with the ends of the first andsecond links 70 and 72 opposite the stand 69. The stand 69, the firstand second links 70 and 72, and the body 74 together function as a fourbar linkage, which is the four bar linkage 66.

It can be understood from FIGS. 16-18 that the driver 68 operativelyextends between the stand 69 and the first link 70. The driver 68 can beany of a wide variety of devices such as pneumatic cylinders, steppermotors, and other such devices that are configured to have a variablelength and to thereby operate the four bar linkage 66 between aretracted position, such as is depicted generally in FIGS. 9-12 and anextended position such as is depicted generally in FIGS. 1, 3, and 5, byway of example. As will be set forth in greater detail below, the fourbar linkage 66 is situated in the retracted position of FIGS. 9-12, byway of example, when the tool 4 is being received in the fuel cell 22and being removed therefrom, whereas the extension apparatus 62 istypically in an extended position, some examples of which are depictedin FIGS. 1, 3, and 5, when an inspection operation or other operation isbeing performed by the tool 4 situated in the fuel cell 22.

As can be understood from FIGS. 13-15, by way of example, the rotationapparatus 64 is situated on the body 74. The rotation apparatus 64 canbe said to include a pair of actuators that are indicated generally atthe numerals 76A and 76B, and which can be collectively or individuallyreferred to herein with the numeral 76. The rotation apparatus 64further includes a crank 68 that is pivotably situated on the body 74and a base 80 that is situated on the crank 78. The actuators 76A and76B each include a cylinder 82A and 82B, respectively, which serves as astationary portion that is mounted to the body 74. The actuators 76A and76B further each include a piston 84A and 84B, respectively, whichserves as an effector that is movable along a telescoping direction withrespect to the corresponding cylinder 82A and 82B. The pistons 84A and84B are operatively connected with the crank 78. As can be understoodfrom FIG. 15, the telescoping direction of the actuator 76A issubstantially parallel with the telescoping direction of the actuator76B, and vice versa. The telescoping direction of the actuators 76 thuscan be said to be substantially parallel with one another. Moreover, theactuators 76A and 76B are situated side by side. In this regard, it canbe seen that the manipulator apparatus 68 includes a free end 85 that issituated at an end of the body 74 opposite the connections with thefirst and second links 70 and 72. The base 80 is situated adjacent thefree end 85, and the actuators 76 both extend away from the crank 78 ina direction that is also away from the free end 85. It can be understoodfrom FIG. 15 that rotation of the base 80 with respect to the body 74 iscaused by the extension of one of the actuators 76 simultaneously withthe contraction of the other of the actuators 76, which results in acoupling of two opposite forces being applied to opposite ends of thecrank 78 simultaneously. The advantageous positioning and coincidentactuation of the actuators 76 enables the free end 85 of the body 74 tobe situated extremely close to the base 80, which advantageously enablesthe device 6 to have a desirably long reach along the axis of elongation34 from the stand 69, as will be set forth in greater detail below.

As can be understood from FIGS. 1, 16, and 17, by way of example, thetool 4 further includes a reciprocation apparatus 86 that is situated onthe base 80 of the rotation apparatus 64. More specifically, thereciprocation apparatus 86 can be said to include a platform 88 that issituated on the base 80 and to further include a support 90 that ismovably situated on the platform 88. The platform 88 can be said toinclude a first side 91A and a second side 91B opposite one another. Thereciprocation apparatus 86 further includes a belt 92 that extendsbetween the platform 88 and the support 90 and a mount 94 that issituated on the support 90 and which includes, for example, a Gimbalapparatus that is interposed between the support 90 and the device 6.The reciprocation apparatus 86 further includes a drive mechanism 96that operatively extends between the platform 88 and the support 90.

The reciprocation apparatus 86 further includes a plurality of retentionwheels 98 that are rotatably situated on the platform 88 and that areengaged with the support 90. In the depicted exemplary embodiment, theretention wheels 98 are in two pairs, with one pair of the retentionwheels 98 movably engaging and retaining therebetween a first portion ofthe support 90, and with the other pair of retention wheels 98 movablyengaging and retaining therebetween another portion of the support 90.In a like fashion, the mount 94 includes a set of four positioningwheels 99 that are rotatably situated thereon and that are similarlyarranged in pairs that are disposed at opposite sides of the support 90and that engage therebetween two different portions of the support 90.

More specifically regarding the support 90, it can be seen that thesupport 90 includes an elongated flange 100 that is elongated along anarcuate path of fixed radius and that is concave with respect to theplatform 88, meaning that the radius of curvature of the flange 100 isin the same direction from the flange 100 as the direction in which theplatform 88 is situated with respect to the flange 100. The flange 100has a first end 101A and a second end 101B opposite one another. Thefirst end 101A extends from the flange 100 in a direction generally awayfrom the first side 91A of the platform 88, and the second end 101Bextends from the flange 100 in a direction generally away from thesecond side 91B of the platform 88. The support 90 further includes atoothed rack 102 that is formed on the flange 100 and that includes aplurality of teeth that are engaged by the drive mechanism 96 to movethe mount 94 among a plurality of positions with respect to themanipulator apparatus 60.

For example, FIGS. 1, 3, and 19-20 depict what could be characterized asa centered position of the reciprocation apparatus 86 which, in thedepicted exemplary embodiment, is wherein the mount 94 is situated asclose as possible to the platform 88, wherein the mount 94 is situatedcentrally on the flange 100 an equal distance between the first andsecond ends 101A and 101B, and wherein the mount 94 overlies theplatform 88. FIGS. 5-8 and 16 depict one extreme position of thereciprocation apparatus wherein the support 90 and the mount 94 (andthus the device 6) are situated as far as possible in onecircumferential direction away from the frame 32. In the position ofFIGS. 5-8, the first end 101A of the flange 100 is situated at alocation spaced relatively farther away from the first side 91A of theplatform 88 than the second end 101B of the flange 100 is spaced awayfrom the second side 91B of the platform 88. In a like fashion, FIG. 17depicts another extreme position of the reciprocation apparatus withrespect to the manipulator apparatus 60 wherein the platform 90 and themount 94 (and thus the device 6) are situated as far as possible in anopposite circumferential direction away from the manipulator apparatus60. In the position of FIG. 17, the first end 101A of the flange 100 issituated at a location spaced relatively closer to the first side 91A ofthe platform 88 than the second end 101B of the flange 100 is spacedaway from the second side 91B of the platform 88. That is, in FIG. 17the second end 101B of the flange 100 is spaced farther away from thesecond side 91B of the platform 88 than the first end 101A of the flange100 is spaced from the first side 91A of the platform 88. FIG. 21depicts an intermediate position intermediate the centered position ofFIG. 19, for example, and the one extreme position of FIG. 16, by way ofexample. It is understood that the reciprocation apparatus 86 iscontinuously movable among all positions between the one extremeposition of FIG. 16, for instance, and the other extreme position ofFIG. 17, by way of example, in order to move the mount 94 and thus thedevice 6 along the circumferential direction 19 between the two extremepositions represented by FIGS. 16 and 17.

As can be seen in FIGS. 19 and 21, for example, the belt 92 has twolocations of affixation that are indicated at the numerals 104A and 104Band which cause the belt 92 to form a closed loop that extends around apair of pulleys indicated at the numerals 105A and 105B that aresituated adjacent the opposite ends 101A and 101B of the flange 100. Thebelt 92 further has an additional location of affixation 104C whereinthe belt 92 is affixed at approximately its midpoint to the platform 88.

As can be understood from FIG. 22, the drive mechanism 96 includes amotor 106 situated on the platform 88 from which extends a shaft 108 andthat is connected with a gear train 110 via an intermediate bevel drive112. The gear train 110 includes a drive gear 114 that is toothed andthat toothedly engages the rack 102 of the support 90. When the motor106 is energized or is otherwise caused to have its shaft 108 rotate,the resulting movement of the drive gear 114 causes the support 90 tomove with respect to the platform 88 since the platform 88 is affixed tothe base 80 of the manipulator apparatus 60. Since the belt 92 isaffixed at the location of affixation 104C to the platform 88, movementof the support 90, such as is indicated in FIG. 21, in a direction awayfrom the centered position of FIG. 19 toward the one extreme position ofFIG. 16 results in the tension in the belt 92 applying a force at thelocation of affixation 104A to the mount 94. Such force causes the mount94 to move with its positioning wheels 99 along the longitudinal extentof the support 90 toward the first end 101A of the flange 100. Suchmovement of the mount 94 can also be said to be generally away from thefirst side 91A of the platform 88.

For each incremental distance of movement of the support 90 with respectto the platform 88 along the circumferential direction 19, the mount 94moves twice as far with respect to the platform 88 along thecircumferential direction 19. This is accomplished by providing the belt92 to extend about both the concave surface of the flange 100, i.e., thesurface upon which the rack 102 is formed, and the convex surface of theflange 100 that is opposite thereto. For example, if the support 90moves one inch along the circumferential direction 19 to the left ofFIG. 21, this results in a portion of the belt 92 being pulled adistance of one inch at each of the concave and convex surfaces of thesupport 90, and since the belt 92 is affixed to the platform 88 at thelocation of affixation 104C, the mount 94 is thereby caused to move atotal of one inch +one inch =two inches along the circumferentialdirection 19 in the leftward direction from the perspective of FIG. 21.The distance along the circumferential direction 19 that is traversed bythe mount 94 in going between the extreme positions of FIGS. 16 and 17is far greater than the length of the support 90 along thecircumferential direction. While a certain portion of the support 90must remain affixed between the pairs of retention wheels 98 on theplatform 88, the geometry presented herein permits the mount 94 and thusthe device 6 situated thereon to move through a distance along thecircumferential direction 19 that is nearly twice the length of thesupport 90 along the circumferential direction 19. Moreover, theprovision of the drive mechanism 96 in combination with the arrangementof the belt 92 enables the drive mechanism 96 to drive both the support90 and the mount 94 with only a single drive mechanism 96.

In order to receive the tool 4 into the BWR 10 for use therein, themanipulator apparatus 60 is first placed into its retracted position,such as is depicted generally in FIGS. 9-12. As can be understood fromFIGS. 9-12, the reciprocation apparatus 86 and the device 6 mountedthereon are situated fully within the receptacle 44 when in theretracted position, thereby permitting the tool 4 to be longitudinallyreceived in one of the fuel cells 22. In the retracted position, thelongitudinal extent of the support 90 is generally aligned with the axisof elongation 34. The manipulator apparatus 60 is typically retained inthe retracted position until the feet 38 have engaged the sockets 24 ofthe fuel cell 22 in which the tool 4 is received. Thereafter, the driver68 can be operated, i.e., lengthened in the depicted exemplaryembodiment, to move the manipulator apparatus 60 from the retractedposition of FIGS. 9-12 to an extended position wherein the support 90 issituated at the exterior of the receptacle 44 with the longitudinalextent of the support 90 remaining generally aligned with the axis ofelongation 34. Further thereafter, the actuators 76 of the rotationapparatus 64 can be operated to pivot the reciprocation apparatus 86between the extended position and a deployed position wherein thesupport 90 has been rotated by the rotation apparatus 64 such that itslongitudinal extent lies approximately transverse to the axis ofelongation 34, such as is depicted generally in FIG. 4.

In so doing, it may also be necessary to energize or otherwise actuatethe motor 42 of the foot apparatus 36 to cause the frame 32 to bepivoted about its axis of elongation 30 with respect to the feet 38,such as is depicted generally in FIG. 2, in order to cause the arcuateprofile of the platform 88 to become aligned with the arcuate profile ofthe interior surface 14 of the shroud 12. In this regard, it can beunderstood that the operation of the manipulator apparatus 60 and thepivot mechanism 40 between the position of FIGS. 9-12 and the positionof FIG. 2 can be accomplished in generally any order so long as thedriver 68 has been operated sufficiently that the support 90 is situatedoutside the receptacle 44. For instance, in a given situation it may bedesirable to operate the pivot mechanism 40 first to cause the frame 32to be oriented in the position depicted generally in FIG. 2, after whichthe driver 68 will be operated to cause the platform 90 to be fullysituated outside the receptacle 44 while not yet being fully situatedclosely adjacent the interior surface 14. The rotation apparatus 64 maythen be energized or otherwise operated to cause the base 80 to berotated approximately 90 degrees to cause the support 90 to be orientedsuch that its longitudinal extent is oriented generally transverse tothe axis of elongation 34. After this, the driver 68 can be furtheroperated to advance the support 90 relatively closer to the interiorsurface 14 until the position that is depicted generally in FIG. 2 isachieved. It thus can be understood that such operations can occur ingenerally any order in order to achieve the positioning of FIG. 2 solong as the support 90 is in the extended position situated outside thereceptacle 44 prior to the rotation apparatus 44 being energized orotherwise operated.

FIG. 2 depicts the same centered position of the reciprocation apparatus86 as FIGS. 1, 3, and 4, by way of example. By energizing or otherwiseoperating the drive mechanism 96, the reciprocation apparatus 86 can becaused to move from the centered position and between the extremepositions of FIGS. 16 and 17, which thereby causes the mount 94 and thusthe device 6 situated thereon to be moved along the circumferentialdirection 19 between a plurality of different positions along theinterior surface 14, i.e., along the circumferential direction 19 at agiven vertical height from the perspective of FIG. 4. Once thereciprocation apparatus 86 has moved between the two extreme positionsof FIGS. 16 and 17, for example, the elevator apparatus 52 can beenergized or otherwise operated to move the manipulator apparatus 60 andthus the reciprocation apparatus 86 and the mount 94, as well as thedevice 6 mounted on the mount 94, to a vertically different positionvertically above or below, from the perspective of FIG. 4, the previousvertical position.

For example, the tool 4 may be initially deployed in the positiondepicted in FIGS. 2 and 4 with respect to the shroud 12, i.e., with thefree end 85 extending from the stand 69 in a direction toward the feet38, which is in a downward direction from the perspective of FIGS. 2 and4, and which can be referred to as a second configuration of themanipulator apparatus 60. The elevator apparatus 52 may be operated toprogressively move the reciprocation apparatus 86 in the downward axialdirection 17 after each traversal by the reciprocation apparatus 86between the extreme circumferential positions such as are depicted inFIGS. 16 and 17. Such circumferential movement alternately followed byaxial movement results in the reciprocation apparatus 86 and thus thedevice 6 moving along successive circumferential sectors of the interiorsurface 14 moving in, for instance, a downward direction to eventuallyinspect a large circumferential sector of the shroud 12 extending fromthe position depicted generally in FIG. 4 downward to the horizontalweld 18.

In this regard, it can be understood from FIG. 6 that the positioning ofthe manipulator apparatus 60 on the elevator apparatus 52 such that itsfree end 85 extends from the stand 69 in a direction generally towardthe feet 38 enables the reciprocation apparatus 86 and thus the device 6to be moved to an extremely low vertical position along the shroud 12.This enables inspection of the horizontal weld 18, by way of example.The tool 4 can thereafter be removed from the fuel cell 22 and the tool4 can be partially disassembled to reorient the manipulator apparatus 60on the elevator apparatus 52 in a first configuration, such as isdepicted generally in FIG. 1, wherein the free end 85 of the manipulatorapparatus 60 extends from the stand 69 in a direction generally awayfrom the feet 38. The first and second configurations mentioned hereinare not intended to suggest any particular order of operation.

Repositioning the tool 4 in the fuel cell 22 with the manipulatorapparatus 60 having been reoriented to be in the second configuration,such as is depicted generally in FIG. 1, enables the elevator apparatus52 to be operated to cause the manipulator apparatus 60 and thus thereciprocation apparatus 86 and the device 6 to be moved vertically veryhigh along the axial direction 17 to enable inspection of the shroud 12in a region adjacent the top guide 26. By enabling the manipulatorapparatus 60 to be switchable between the two configurations of FIG. 1and FIG. 5, for example, the manipulator apparatus 60 is alternatelypositioned to enable the entire vertical extent of the shroud 12 to beaccessible by the device 6, such as for inspection or for otherpurposes. It is reiterated that operation of the reciprocation apparatus86 enables a wide swath along the circumferential direction 19 that isnearly twice the length of the support 90 along the circumferentialdirection 19 to be accessed by the mount 94 and thus the device 6 forpurposes of inspection or otherwise while the tool 4 is received in agiven fuel cell 22. A bail 116 situated at the top of the frame 32enables the tool 4 to be connected with a lifting mechanism that lowersthe tool into the relevant fuel cell 22 and removes the tool 4therefrom.

It can be understood that the computer system 28 is operable to performall of the operations set forth above and to control the device 6, suchas by detecting ultrasonic data therefrom during a testing operation orto otherwise control a different type of device 6 that otherwiseinteracts with the shroud 12. The configuration of the tool 4 and thereciprocation apparatus 86 thus advantageously enable rapid access tothe interior surface 14 of the shroud 12 which enables inspection orother operations to be rapidly performed thereon. Other advantages willbe apparent.

While specific embodiments of the disclosed concept have been describedin detail, it will be appreciated by those skilled in the art thatvarious modifications and alternatives to those details could bedeveloped in light of the overall teachings of the disclosure.Accordingly, the particular arrangements disclosed are meant to beillustrative only and not limiting as to the scope of the disclosedconcept which is to be given the full breadth of the claims appended andany and all equivalents thereof.

What is claimed is:
 1. A tool that is structured to be received into aninterior region of a core shroud of a boiling water reactor and that isstructured to carry a device thereon into the interior region, the toolcomprising: a frame, the frame being elongated along an axis ofelongation and having a receptacle formed therein that is elongatedalong the axis of elongation; an elevator apparatus situated on theframe; a manipulator apparatus situated on the elevator apparatus, atleast a portion of the manipulator apparatus being situated in thereceptacle; a reciprocation apparatus comprising a support that iselongated and that is situated on the manipulator apparatus, thereciprocation apparatus further comprising a mount that is situated onthe support and that is structured to carry the device; the elevatorapparatus being operable to move the manipulator apparatus between afirst position and a second position along the longitudinal extent ofthe frame; the manipulator apparatus being operable to move thereciprocation apparatus between a first position wherein the support isdisposed at least in part in the receptacle and a second positionwherein the support and the mount are removed from the receptacle; and afoot apparatus situated on the frame and comprising a number of feet anda pivot mechanism, the number of feet being situated at an end of theframe and being structured to be received on at least one of a fuelsupport, a control rod guide tube, and a core plate of the boiling waterreactor, the pivot mechanism being structured to pivot the frame aboutthe axis of elongation with respect to the number of feet when thenumber of feet are received on the at least one of the fuel support, thecontrol rod guide tube, and the core plate.
 2. The tool of claim 1wherein the frame includes a head that is situated at another end of theframe and that is elongated along the axis of elongation, the head beingof a circular profile in a plane transverse to the axis of elongation.3. The tool of claim 2 wherein the head has formed therein an accessport that is structured to receive therein another device.
 4. The toolof claim 1 wherein the manipulator apparatus comprises an extensionapparatus situated on the elevator apparatus and a rotation apparatussituated on the extension apparatus, the extension apparatus beingoperable to move the reciprocation apparatus between the first positionand second positions, the rotation apparatus being operable to rotatethe support with respect to the extension apparatus.
 5. The tool ofclaim 4 wherein the extension apparatus comprises a four bar linkage,and wherein the rotation apparatus is situated on a bar of the four barlinkage.
 6. The tool of claim 5 wherein the rotation apparatus comprisesa pair of actuators extending between the bar and the support, eachactuator of the pair of actuators comprising: a stationary portion; aneffector that telescopes with respect to the stationary portion along atelescoping direction; and one of the stationary portion and theeffector being situated on the bar, the other of the stationary portionand the effector being connected with the support.
 7. The tool of claim6 wherein the telescoping direction of each actuator of the pair ofactuators is oriented substantially parallel with the telescopingdirection of the other actuator of the pair of actuators.
 8. The tool ofclaim 7 wherein the support comprises a crank, the other of thestationary portion and the effector of each actuator of the pair ofactuators being operatively connected with the crank, the crank beingsituated between the effectors.
 9. The tool of claim 7 wherein thestationary portions are situated side-by-side.
 10. The tool of claim 4wherein the support is elongated along an arcuate path that is of afixed radius.
 11. The tool of claim 4 wherein the manipulator apparatusis mountable on the elevator apparatus in either of a pair ofconfigurations: in a first configuration of the pair of configurations,the extension apparatus in the first position extends from the elevatorapparatus in a direction generally toward the foot apparatus; and in asecond configuration of the pair of configurations, the extensionapparatus in the first position extends from the elevator apparatus in adirection generally away from the foot apparatus.
 12. The tool of claim1 wherein the frame has at least one of a number of chamfers and anumber of radii that are formed on an exterior surface thereof and thatextend along the axis of elongation.